Recovering nitrogen bases from mineral oils



July 28, 1942- B. R. sTRlcKLAND 2,291,419

RECOVERING NITROGEN BASES FROM MINERAL OILS Filed oct. s1, 1940 Per/Pouw Pima/.san 0u, Y 3 l 1 Jou/45 l 0/1. Sou/.avr

l A//rkosf'u v @was RECOVERY ZONE wam? CHI/J TIC 24 A/Eur/ML/z/qr/an/ 17d/0 ONE BHMW 2f mm 2 Patented July 28, 1942 RECOVERING NITROGEN BASES FROM MINERAL OILS Barney R. Strickland, Roselle, N. J., assignor to Standard Oil Development Company, a corporation of Delaware Application October 31, 1940, Serial No. 363,639

7 Claims.

The present invention relates to the refining of mineral oils. The invention is, however, more particularly concerned with the removal and recovery of naturally occurring nitrogen bases from mineral oils containing the same. In ac-cordance with the present process these materials are recovered in an efficient and economical manner by a process utilizing bauxite.

It is Well known in the art to treat petroleum oils with various solid treating agents, as for example bauxite, zeolte and the like in order to improve their color and color stability. It has also been proposed to use these substances for the recovery and segregation of naturally occurring acidic oxygen-containing compounds, as for example petroleum naphthenie acids and petroleum oil phenols.

I have now discovered a process by which valuable naturally occurring nitrogen bases may be recovered from feed oils containing the same utilizing bauxite. In accordance with my invention, feed oils containing recoverable nitrogen bases are contacted preferably With activated bauxite under conditions to substantially fully remove these constituents from the feed oils. The spent bauxite containing the adsorbed nitrogen bases is then handled in a manner to remove and segregate these constituents in a relatively pure state and to fully regenerate the bauxite which is preferably recycled and contacted with fresh feed oil. The process of my invention may be readily understood by reference to the attached draW- ing illustrating modications of the same.

For purposes of description, it is assumed that the feed oil is passed through a bed of bauxite although it is to be understood that a continuous operation may be employed in which, if desired, a slurry of bauxite is utilized. Referring specifically to the figure, it is also assumed that the nitrogen base containing feed oil is a petroleum oil boiling in the kerosene boiling range. The feed oil is introduced into initial contacting zone I by means of feed line 3. It is to be understood that any number of zones may be utilized and may be arranged in any suitable manner. The feed oil flows upwardly through zone I and contacts a bed of bauxite which preferably comprises a small particle size so that a relatively large surface area is secured. Temperature and pressure conditions are adjusted in a manner so as to substantially completely remove the nitrogen bases comprising aryl and alkyl amines and complex derivatives of pyridine, quinoline, pyrrole, and pyrazole from the feed oil. The feed oil is Withdrawn from initial contacting Zone I by means of line 4, Withdrawn from the system, and handled in any manner desirable. At the end of a fixed time period in which the effectiveness of the bauxite decreases to a predetermined efliciency, the feed oil is passed into secondary bauxite contacting zone 2 by means of line 5, and Withdrawn by means of line 6.

The spent bauxite in contacting zone 1 containing the adsorbed nitrogen bases is handled in a manner to remove and segregate these coinpounds and to regenerate the bauxite. This is preferably accomplished by washing the bauxite with suitable solvents. For the purposes of description it is assumed that the bauxite is initially contacted with a relatively loW boiling petroleum oil solvent having a preferential solubility for petroleum feed Oil constituents remaining in the bauxite bed. This petroleum oil washing solvent may be introduced into contacting zone I by means of line 'I and withdrawn by means of line 8. The bauxite bed is then contacted with a solvent having a preferential selectivity for the nitrogen base compounds, Which for the purpose of description is taken to be water. The Water is introduced into initial contacting zone I by means of line 9 and Withdrawn by means of line I0. Suiicient Water is introduced at a temperature and pressure which is adapted substantially fully to remove the nitrogen base compounds from the spent bauxite bed. The bauxite bed, free of petroleum feed oil and adsorbed nitrogen bases and related compounds,

' is then contacted and treated in a manner adapted to fully regenerate the same, after which it is contacted with additional fresh feed oil.

At the end of the cycle in which the eiciency cf the bauxite in contacting zone 2 drops to a predetermined value, the fresh feed oil is again passed into the regenerated bauxite in zone I. The bauxite in contacting zone 2 containing the adsorbed nitrogen bases is then handled in a manner similar to that described With respect to Zone I in order to remove and segregate the nitrogen bases and to regenerate the bauxite. This is accomplished by initially Washing the bauxite bed with a relatively 10W boiling petroleum oil solvent which is introduced by means of line II and Withdrawn by means of line I2. The adsorbed nitrogen bases are removed by contacting the bauxite with a preferential solvent for the nitrogen base compounds which is introduced by means of line I3 and Withdrawn by means in which the nitrogen bases are removed overhead by means of line I 'I and the Water removed The nitrogen as a bottoms by means of line I3.- bases may be further refined'or handled in any desirable manner.

When the feed oil containingthe nitrogen bases also contains petroleum oil phenols, theselatter materials are likewise adsorbed on the bauxite and removed in the aqueouslayer. Under these conditions the aqueous solutions removedzfrom the respective contactingvzones I- andpby means of lines I and I4, respectively, are; handled` in a manner to segregate the nitrogenbases from` the` phenolic type compounds;v This is preferably accomplished, by introducing the aqueous solution into treating plantV ISB-,by means of line 20, in which it is contacted With a dilute mineral acid solution such as a dilute sulfuric acid solution which is introduced by meansgof line. 2i. The upper layer comprisingphenolic constituents is removed by means of line, 2l While the lower layer comprising a dilute sulfuric acid solution extract containing thernitrogenbases is removed.

bymeans of line 22 and passedy into neutralization unit 23. In neutralization, unit 23 the acid` layer is contacted with a neutralization agent,

as forerxample caustic soda, which is introduced;

by means of line 2d under conditions, to neutralize the acidic constituents. Under thesecom ditions the nitrogen bases separate as. an upper layer and are removed from neutralization-'unit 23 by means of line 25- while theaqueous layer is removed by means of line 26.

The process of the present invention may. be, widely varied. It is to be understood that eitherv a batch operation oral continuous operation as for example, utilizingabauxite;V slurry may be employed. The feed oil may be anykmineral oil,

but preferably comprises petroleum oils boiling in the range from about 300 lto 600 F., preferably boiling in the range fromaboutiOO-fy F. to 550 F. In general the feed oilsshould preferably comprise oilswhich are free ofnaturally occurring acidic oxygen containing compounds as for example phenols andnaphthenic acids and contain nitrogen bases comprising aryl and alkyl amines and complex 'derivatives of pyridine, quinoline, pyrrole, and pyrazole.

The bauxite. preferably comprises a. native aluminum hydroxide containing from 50% to In general it is preferred that the bauxite be activated by burning thesame ata temperature above about 500 F. to 900 F., preferably at a temperature from about 600 F. to'800 F;

The operating conditions likewise may be Widely modied. IThe ow of the'respective treating agents may be either upfiow ordown-flow; Temperatures. and pressures may; vary andY will depend upon the particular feed oil beingtreated,

thequantity and character of thel nitrogen'bases present, as Well as upon the particular bauxite being used and upon the feed rates andparticle For purposes of illustration it is assumedl that recovery Zone I comprises a separation unitsize. In general it is preferred to employ ate mospheric temperatures and pressures, although temperatures in the range from about 30 F. to 250 F. may be employed in particular instances. If the petroleum oil be of a relatively high viscosity, it may be desirable to employ heating means or to dilute the oil with an inert dilution solvent, as for exampleu a relatively low boiling petroleum oil or with a relativelylow boiling hydrocarbon constituent.

The feed rates may vary considerably depending upon thegeneral operating conditions, the character of the feed oil being treated, as Well as upon the type of bauxite being employed. When theprocess-comprisesthe utilization of stages, feedf ratesare inthe general range from one to seven volumes of oilper Volume of bauxite per hour. The preferred rates are from two to four volumes of oil per volume of bauxite per hour. When employing a slurry, the amount of slurry is preferably in the range from one volumerof bauxite per fifteen to :twenty-five Volumeswofoil:V4

Although it is not essential, itis preferred-that the bauxite-after contactwith the oil be 'washed with a solvent Which Willremoveoccluded'oilv portions4 from the bauxiteY prior to .treating the?. bauxite to remove the adsorbed nitrogen bases. This solvent may bel any relatively low. boiling hydrocarbon. A desirable material' comprises naphtha boiling in the range from.about200 F;

to 300 F.

The nitrogen bases are. preferably... removedv from the bauxiteby treating. Withwater at1nor.- mal temperatures andpressures. Thel amount of.I Water employed may vary Widely dependinggupon the quantity of nitrogen basespresent and. thev particular bauxite employed. Ingeneral it. is preferred to employ from about one to fourvol'- urnes of Water per volume of bauxite in Yorder to: displace the nitrogen compounds. A preferred` modification of utilizing water at normaltemperatures and pressures, for thedisplacementof.y the nitrogen compounds Ais to agitato they massf with air or a similar. agitating means.- Undercere. tain conditions it may be` desirablejtoemploy: heated Water or steam in order to removezthe nitrogen bases, although inA general` this methodrvr is not preferred. II" steam beV employed itis pre,- ferred that the steam operationbaconducted at a temperature in the. range from about 600?A to 800 F; The aqueous.,solution,after. removal.v

from the bauxite bed, will form two phases com.-V prising a nitrogen base phaseand'anaqueous phase. The nitrogen base phase. is separated and may be further renedin any mannen defsirable. Although the aqueous phasey maybe distilled inA order to remove any relativelyA low` boiling soluble nitrogen4 compounds present, it. is preferred to recirculate the sameas asolvent directly lto the bauxite contacting units:

When the feed oil also contains naturally occurring oxygen containing acidic compounds; as'A for example phenols and naphthenicA acids,J thef aqueous solution removed from the bauxite is contacted with a mineralv acid,V as for exam-pleV sulfuric acid. Preferredresults aresecuredwhen` the aqueous solution is contactedvv-ith adilute sulfuric acid solutionhaving `a `conceniuation-in the range from 20 to 50%. This-concentration-- of course will vary dependingupon the type of' nitrogen bases present, the type ofA naturally-foccurring oxygen containingl acidic compounds present,l as Well as upon the-*concentrationY ofithe respective constituents.- When using asul'- furic :acid solutionofthis concentration it is.

A feed oil comprising 100 milligrams of nitrogen bases per 100 milliliters of feed oil was percolated through bauxite having a specific gravity of about 0.8 and a mesh of about 30 to 60. Atmospheric temperature and pressure was employed. The feed rate used was one volume of feed oil per volume of bauxite per hour. A yield of 16 volumes of nitrogen base-free filtrate per volume of bauxite was obtained.

The quality of the treated oil as compared to the feed oil was improved as seen by the following:

Direct Color oxidation Saybolt color,

Feed oil +24 8 R Treated oil +27 +26 S *Refer to van Senden, Proc. World Pet. Cong. II, 1933.

The bauxite was washed with a light petroleum oil solvent and the nitrogen bases then recovered from the bauxite by treatment with water.

Example 2 A feed oil comprising 100 mg. of pyridine per 100 ml. of oil was passed through burned Alabama bauxite at room temperature. The feed rate was one volume of oil per volume of bauxite per hour. A yield of fteen volumes of pyridine free oil per Volume of bauxite was secured. The bauxite was treated with a petroleum oil solvent and the nitrogen bases then removed by treatment with water.

What I claim as new |and wish to protect by Letters Patent is:

1. Process for the segregation and recovery of nitrogen bases from oils comprising contacting a nitrogen base containing feed oil with bauxite under conditions to remove the nitrogen bases from the treated oil, separating the bauxite from the feed oil and removing the nitrogen bases therefrom by means of an aqueous solvent, removing the aqueous solvent and recovering the nitrogen bases.

2. Process in accordance with claim 1 in which said aqueous solvent is water, and in which the nitrogen bases are recovered from said solvent by distillation.

3. Process in accordance with claim 1 in which said feed oil is a petroleum oil which boils in the ra ge from about 300 F. to about 600 F.

4. Process for the segregation and recovery of nitrogen bases from oils containing phenolic type constituents comprising contacting a feed oil containing nitrogen bases and phenolic type constituents with bauxite under conditions to remove the nitrogen bases from. the feed oil, separating the treated feed oil and treating the bauxite with an aqueous solvent for the nitrogen bases, removing the aqueous solvent containing the nitrogen bases, treating the solvent with a weak mineral acid whereby the nitrogen bases separate from phenolic type constituents, sepahating the resulting acid 1ayer, neutralizing the same and recovering the nitrogen bases therefrom.

5. Process in accordance with claim 4 in which said solvent is water.

6. Process in accordance with claim 4 in which said feed oil is a petroleum oil which boils in the range from about 300 to about 600 F.

7. Process for the segregation and recovery of nitrogen bases from mineral oils comprising contacting a nitrogen base containing feed oil with bauxite under conditions to remove the nitrogen bases from the treated feed oil, separating the bauxite and treating the same with Water, removing the aqueous solution whereby la higher boiling nitrogen base phase separates as a separate phase, separating said nitrogen base phase from the aqueous phase, distilling said aqueous phase to segregate relatively low boiling nitrogen bases therefrom.

BARNEY R. STRICKLAND. 

